Internal combustion engine and supercharging apparatus



DEG 1942. H. OSWALD 2,306,277 INTERNAL COMBUSTION EFNGINE AND SUPERCHARGING APPARATUS Filed May 16, 1939 FUEL EEGUL 1970K 5' INVENTOR .lyazzs flan aid ATTORNEYS Patented Dec. 22, 1942 mama comius'non ENGINE nun rnncmome srranarus 1 Hans omud, .Winterthnr, Switzerland, assignmto Sulzer Freres, Socite Anonyme, Winterth Switzerland Application May 16, 1939, Serial No. 273,922

InSwitzei-land June 22, 1938 v 2Claims.

The invention relates 'to internal combustion engines having" supercharging apparatus, and particularly to .engines which'are used under varying barometric pressures .such as engines which are moveds through wide ranges in altitude. The invention aims toprovide an improved supercharging apparatus for maintaining automatically the supercharging pressure at predetermined pressures.

blowers, one of which is variably controlled by a regulating device, responsive to changes in the pressure of the supercharging air.

Many difiiculties have been encountered heretofore in attempting to provide supercharging apparatus that will functioneconomically on The apparatus of the invention comprises at least two superchargingengines moved through wide'ranges in altitude;

in other words, engines which operate under fluctuating barometric pressures. -It is desirable from a standpoint of engine performance that the supercharging pressure he at the same absolute value andgthe temperature constant, but

this. would require the compression ratio to change very greatly from high to, low altitudes.

In a singlefsupercharging blower havinga number of stages, this can be accomplished only in an incomplete way. Large changes in the compression ratio are possible economically only when the number of. the compression stages is increased with increasing height above sea level.

Even where multiple'blowers are connected in less schematically apparatus embodying theinvention, in which:

Fig. 1-is a plan view of one term of according to the invention;

Fig. 2 is a plan view of another form of apparatus according to the invention; and

' Fig. 3 is a plan view of a different form of ap- 1 paratus according to the' invention.

The apparatus illustrated in the drawing comprises an internal combustion engine E which,

may be connected to any suitable load such as a generator G shown in Fig. 1 together with the load-engine-control apparatus including a; fuel regulator R responsive to engine speed, field excitation means F for regulating the load of the generator, a control device C responsive to the pressure of the supercharging air supplied to the engine, and a servo-motor S connected to the fuel regulator, the field excitation means and the control device by suitable coupling members'M, whereby the load is regulated in accordance withv the speed and the supercharging air pressure.

The engine is provided with supercharging apparatus comprising a directly driven primary blower 2 and a secondary blower 3 variably controlled in accordance with the pressureof the series and work independently of one another,

the number .of the compression stagesremains the same. The ainf to utilize the internal combustion engine to the fullest extent possible in all altitudes 'is therefore not attained. When such blowers work at, high barometric pressure,

the compression ratio-must be reduced artifl-' cially, that is to-say, air must be let ofi. How ever, such compressors do not workeconomically.

The invention aims to avoid the aforementioned disadvantages. In the apparatus of ,the invention, one blower serves for supplying super charged air under all conditions of altitude and barometric pressure (hereinafter referred to as the primary supercharging blower), while the other blower (hereinafter referred to as the secondary superchargingblower) serves only to supply additional supercharged airat higher altitudes. This makes it possible by simple means to adaptjthe compression ratio, with economical working of the blowers, to the initial pressure orto the pressure ofthe surrounding air.

The accompanying drawing illustrates more or superchai ged air.

, In the apparatus of Fig. 1, the primaryblower Y 2 is driven directly from the engine by a transmission gear 4. The primary blower 2 draws in the ambient air and discharges it into a conduit 6; preferably provided with cooling fins I, which connects to the intake side of the secondary blower 3. The discharge side of' the blower 3 connects to the air manifold 8 which is arranged to supply the various-cylinders of the engine with v the supercharging air in the usual way. The various cylinders of the engine exhaust into the exhaust 'manifold 9 connected to the exhaust turbine III which is coupled by drive means to the secondary blower 3. The exhaust turbine drives the blower 3 and discharges its spent gases through the exhaust device H. The exhaust manifold'll is provided with a flap valve l2v :arranged to pass allor a part of the gas to the turbine ill, or to pass all or a part of 'the'gas to the atmosphere through the by-pass opening I3. The valve 12 is operated by a control device l5 having a servo-motor IS, the piston H- of which is operatively' connected'to the valve l2. The

servo-motorcylinder l9'has passages 20 and 2|, v a control piston or valve 22 and an expansible bellows 123 connected to the shaft 24 on which the valve 22 is mounted.- The bellows 23 is inside a'chamber 25. connected by conduit 26 to the apparatus fold remains closed, that is, in the position I. When the supercharging air pressure increases, the valve 22' is moved toward the. right. Only after having traversed the valve path a, does the valve reach its central position: Ifthe pressure increases still further, the supply of pressure medium to the right side of the cylinder l9 will be I opened and the piston I1 is movedtoward the 2,306,277 I I p v electric motor 30 and the output of the blower 3 positi n and the valve i2 in the exhaust manileft, which opens the valve permitting-the exhaust gases to emerge through the by-pass outlet l3.

When the supercharging air pressure falls again, the valve 22 reaches the central position, in which the left as well as the right side of the cylinder i9 is shut off from the supply of pressure medium. In this position the piston I1 and the valve l2 take a definite position, which corresponds to the compressidn ratio necessary inorder to attain the value of the supercharging air pressure that is to be maintained constant are lowered. i

In the position IV of the contact lever 32, the motor is cut out and the blower 3 is stopped.

' In the position III of the contact lever 32, the

motor 3llruns at highest speed. The supercharg-.

ing air, pressure will therefore be maintained.

constant temporarily in a certain: range by the regulation of the speed of the motor 30. The regulation of the speed of the motor 30 can also be eifeoted in any other suitable way, for example by a resistance connected in the shunt field circuit, or through tapping of the field of the motor 30.-

In the form of apparatus illustrated in Fig. 3, the manifold 3 connects to a turbine -which is coupledto and drives theblower 2. Iurbine '35 is connected by conduit 36 to the turbine 31 in such way that the exhaust of turbine 35 drives the turbine 31. The turbine 31 exhausts to the atmosphere through the opening-38. The turbine 31 is coupled to anddrives the secondary blower 3. The, outlet side of the primary or directly driven blower 2 is connected by conduit to the intake side of blower 3, the outlet side of which connects to the air manifold 8. Theconduit 36- has a by-pass opening ll and a flap-valve 4 2 arranged to discharge the exhaust from turbine 35 at a given pressure ofthe surrounding air. In

this case the total compression ratio can be dis-.

tributed to the two compressors in difierentways. From a definite pressure of the ambient air onwards the'supply of exhaust gases to the turbine 10 can be controlled by-means of the valve II.-

The turbine l fl'may be supplied with a maximum quantity of exhaust gas, as when the valve i2 is in position I, or the turbine Ill may be shut oil from exhaust'gas as when the valve 12 is in the position II. In other words the exhaust turbinemay be shut down, operated at a maximum or at the discharge side of which is connected by conduit to the intake side of the secondary blower 3 and the compressed air passes through blower 3, enters the air manifold 8 and passes into the engine. The blower 3'is driven by the electric motor 30 controlled by apparatus actuated by the pressure of the supercharged air comprising a resistance 3| for the regulation of the motor,

a contact lever 32 operated by a control device I5 similar to the control device ii of Fig. 1.- "The control, device connects by conduit to the manifold 8 and swings the lever 32 between the in the pressure of thes'uperchargingair.

As long as the internal combustionengine is I in operation, the waste gases pass through the manifold 9 to the turbine 2'! and from thereinto the exhaust 28 sothat the blower 2 is constantly in operation. On the other hand, the blower 3 is independently driven by the electric motor 33.

It is only temporarily in operation according to.

the initial pressure of the air, since the regulatlng device 15 cuts in stages of the resistance 3! when a definite value of the supercharging air pressure is exceeded. 'I'h'erebythe output of the Y limits of positions III and IV due to variations to the;atmosphere or to. permit all or a part The valve 42' thereof to pass to the turbine 31. is connected to a control, device I5 which is connected by pipe 43 to the air manifold, 8. The

control device I5 and valve 42 are constructed and operated in substantially the same manner as the controldevice l5 and valve i2 of Fig. 1.

As shown in Fig. 3,'the"blower 2 and the blower- 3 are. driven by exhaust gas turbines 35 and 31 respectively which are connected in series. The

regulating device I5 controls the outlet valve 42- in the conduit 36 between the turbine 35 and the turbine 31. At the'lowest barometric pressure ordinarily encountered, the valve 42 shuts ot! the outlet II. The exhaust gas turbine 31 then drives the blower 3 for maximum output. If the barometric pressure exceeds a definite value, which; depends on the value of the supercharging air pressure-that is to be-maintained constant and also on the load, the output of the ex-' h'aust gas turbine 31 is regulated by means-of thereg'ulating device ii to provide the supercharging airipressure desired. The regulating:-

device may cause the valve 42 to open the by-pas's 4| and completely shut oil-the admission of the variably operated between the limits described in connection with Fig. 1.

Ordinarily a is desirable to endeavour to obtain the same absolute supercharging pressure at I all barometric pressures, when the highest available output is to be obtained with a certain engine. If a substantial part or the whole compression work forthe char ing air is produced with the "aid of the energy contained in the exhaust' gases, limits are. set to the compression ratio attainable in a blower driven in this way. since the energy which is available in practice and which is contained in the exhaust gases is suflicient only up to a definite altitude or a definite lower limit of the barometric pressure to bring the total quantity of air to the desired supercharging pressure. If one of the blowers is driven electrically or is 'driven directly by the engine, then the amount of the supercharging pressure to be attained is limited to a lesser extent. But even then, in special cases, it is advisable to forego the production of\the highest supercharging pressure in t e reater altitudes, for example, when the ascents are not steep and the highest available output is not required.

In directly driven blowers, the compression ratio is dependent on the speed and at constant speed is approximately constant, so that it can be advantageous to select the compression ratio.

of the directly driven blower so that the blower can produce the desired supercharging pressure at the highest barometric pressure that may ocour, and thereby the advantage results that only the second blower needs to be regulated and thus the total compression ratio adapts itself to the change of the barometric pressure.

What I claim is:

secondary blower to the air manifold, a control device connected to the air manifold actuated by the pressure oifthe supercharging air, and means actuated by Jjthe control device controlling the operation of'the second turbine. v

2. A supercharged internal combustion engine which comprises a primary supercharging blower, a first turbine driven by exhaust gas from the engine operatively connected to the primary supercharging blower, a secondary supercharging blower connected in series to the primary supercharging blower, a, second turbine connected to 4 and arranged to be driven by exhaust gas from 1. An internal combustion engine and super- I charging apparatus which comprises a first turbine driven by exhaust gas from the engine, a primary superchar'ging blower driven by the first turbine, a second turbine connected by conduit to the exhaust side of the first turbine and driven by the exhaust gas therefrom, a secondary supercharging blower driven by the second turbine, an air manifold for delivering-supereharging air to the engine cylinders, conduit connecting the primary and secondary blowers in series and the the first turbine, said second turbine being operatively connected to the secondary supercharging blower, conduit means for Passing supercharged air from the primary supercharging blower through the secondary supercharging blowerand into the engine cylinders, a control device, a conduit for imposing the pressure of the supercharging air upon the control device, and means for controlling the operation of the second turbine connected to and under the control of the control device, whereby the pressure of the supercharging air acting upon the control device controls the supercharging air supplied to the engine.

HANS OSWALD. 

